1 /* 2 * linux/arch/sh/kernel/signal.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson 7 * 8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 9 * 10 */ 11 #include <linux/sched.h> 12 #include <linux/mm.h> 13 #include <linux/smp.h> 14 #include <linux/kernel.h> 15 #include <linux/signal.h> 16 #include <linux/errno.h> 17 #include <linux/wait.h> 18 #include <linux/ptrace.h> 19 #include <linux/unistd.h> 20 #include <linux/stddef.h> 21 #include <linux/tty.h> 22 #include <linux/elf.h> 23 #include <linux/personality.h> 24 #include <linux/binfmts.h> 25 #include <linux/io.h> 26 #include <linux/tracehook.h> 27 #include <asm/ucontext.h> 28 #include <asm/uaccess.h> 29 #include <asm/pgtable.h> 30 #include <asm/cacheflush.h> 31 #include <asm/syscalls.h> 32 #include <asm/fpu.h> 33 34 struct fdpic_func_descriptor { 35 unsigned long text; 36 unsigned long GOT; 37 }; 38 39 /* 40 * The following define adds a 64 byte gap between the signal 41 * stack frame and previous contents of the stack. This allows 42 * frame unwinding in a function epilogue but only if a frame 43 * pointer is used in the function. This is necessary because 44 * current gcc compilers (<4.3) do not generate unwind info on 45 * SH for function epilogues. 46 */ 47 #define UNWINDGUARD 64 48 49 /* 50 * Do a signal return; undo the signal stack. 51 */ 52 53 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ 54 #if defined(CONFIG_CPU_SH2) 55 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ 56 #else 57 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ 58 #endif 59 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ 60 61 struct sigframe 62 { 63 struct sigcontext sc; 64 unsigned long extramask[_NSIG_WORDS-1]; 65 u16 retcode[8]; 66 }; 67 68 struct rt_sigframe 69 { 70 struct siginfo info; 71 struct ucontext uc; 72 u16 retcode[8]; 73 }; 74 75 #ifdef CONFIG_SH_FPU 76 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) 77 { 78 struct task_struct *tsk = current; 79 80 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 81 return 0; 82 83 set_used_math(); 84 return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0], 85 sizeof(long)*(16*2+2)); 86 } 87 88 static inline int save_sigcontext_fpu(struct sigcontext __user *sc, 89 struct pt_regs *regs) 90 { 91 struct task_struct *tsk = current; 92 93 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 94 return 0; 95 96 if (!used_math()) 97 return __put_user(0, &sc->sc_ownedfp); 98 99 if (__put_user(1, &sc->sc_ownedfp)) 100 return -EFAULT; 101 102 /* This will cause a "finit" to be triggered by the next 103 attempted FPU operation by the 'current' process. 104 */ 105 clear_used_math(); 106 107 unlazy_fpu(tsk, regs); 108 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu, 109 sizeof(long)*(16*2+2)); 110 } 111 #endif /* CONFIG_SH_FPU */ 112 113 static int 114 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) 115 { 116 unsigned int err = 0; 117 118 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) 119 COPY(regs[1]); 120 COPY(regs[2]); COPY(regs[3]); 121 COPY(regs[4]); COPY(regs[5]); 122 COPY(regs[6]); COPY(regs[7]); 123 COPY(regs[8]); COPY(regs[9]); 124 COPY(regs[10]); COPY(regs[11]); 125 COPY(regs[12]); COPY(regs[13]); 126 COPY(regs[14]); COPY(regs[15]); 127 COPY(gbr); COPY(mach); 128 COPY(macl); COPY(pr); 129 COPY(sr); COPY(pc); 130 #undef COPY 131 132 #ifdef CONFIG_SH_FPU 133 if (boot_cpu_data.flags & CPU_HAS_FPU) { 134 int owned_fp; 135 struct task_struct *tsk = current; 136 137 regs->sr |= SR_FD; /* Release FPU */ 138 clear_fpu(tsk, regs); 139 clear_used_math(); 140 err |= __get_user (owned_fp, &sc->sc_ownedfp); 141 if (owned_fp) 142 err |= restore_sigcontext_fpu(sc); 143 } 144 #endif 145 146 regs->tra = -1; /* disable syscall checks */ 147 err |= __get_user(*r0_p, &sc->sc_regs[0]); 148 return err; 149 } 150 151 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5, 152 unsigned long r6, unsigned long r7, 153 struct pt_regs __regs) 154 { 155 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 156 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; 157 sigset_t set; 158 int r0; 159 160 /* Always make any pending restarted system calls return -EINTR */ 161 current_thread_info()->restart_block.fn = do_no_restart_syscall; 162 163 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 164 goto badframe; 165 166 if (__get_user(set.sig[0], &frame->sc.oldmask) 167 || (_NSIG_WORDS > 1 168 && __copy_from_user(&set.sig[1], &frame->extramask, 169 sizeof(frame->extramask)))) 170 goto badframe; 171 172 set_current_blocked(&set); 173 174 if (restore_sigcontext(regs, &frame->sc, &r0)) 175 goto badframe; 176 return r0; 177 178 badframe: 179 force_sig(SIGSEGV, current); 180 return 0; 181 } 182 183 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5, 184 unsigned long r6, unsigned long r7, 185 struct pt_regs __regs) 186 { 187 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 188 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; 189 sigset_t set; 190 int r0; 191 192 /* Always make any pending restarted system calls return -EINTR */ 193 current_thread_info()->restart_block.fn = do_no_restart_syscall; 194 195 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 196 goto badframe; 197 198 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 199 goto badframe; 200 201 set_current_blocked(&set); 202 203 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) 204 goto badframe; 205 206 if (restore_altstack(&frame->uc.uc_stack)) 207 goto badframe; 208 209 return r0; 210 211 badframe: 212 force_sig(SIGSEGV, current); 213 return 0; 214 } 215 216 /* 217 * Set up a signal frame. 218 */ 219 220 static int 221 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 222 unsigned long mask) 223 { 224 int err = 0; 225 226 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) 227 COPY(regs[0]); COPY(regs[1]); 228 COPY(regs[2]); COPY(regs[3]); 229 COPY(regs[4]); COPY(regs[5]); 230 COPY(regs[6]); COPY(regs[7]); 231 COPY(regs[8]); COPY(regs[9]); 232 COPY(regs[10]); COPY(regs[11]); 233 COPY(regs[12]); COPY(regs[13]); 234 COPY(regs[14]); COPY(regs[15]); 235 COPY(gbr); COPY(mach); 236 COPY(macl); COPY(pr); 237 COPY(sr); COPY(pc); 238 #undef COPY 239 240 #ifdef CONFIG_SH_FPU 241 err |= save_sigcontext_fpu(sc, regs); 242 #endif 243 244 /* non-iBCS2 extensions.. */ 245 err |= __put_user(mask, &sc->oldmask); 246 247 return err; 248 } 249 250 /* 251 * Determine which stack to use.. 252 */ 253 static inline void __user * 254 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 255 { 256 if (ka->sa.sa_flags & SA_ONSTACK) { 257 if (sas_ss_flags(sp) == 0) 258 sp = current->sas_ss_sp + current->sas_ss_size; 259 } 260 261 return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul); 262 } 263 264 /* These symbols are defined with the addresses in the vsyscall page. 265 See vsyscall-trapa.S. */ 266 extern void __kernel_sigreturn(void); 267 extern void __kernel_rt_sigreturn(void); 268 269 static int setup_frame(int sig, struct k_sigaction *ka, 270 sigset_t *set, struct pt_regs *regs) 271 { 272 struct sigframe __user *frame; 273 int err = 0; 274 int signal; 275 276 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 277 278 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 279 goto give_sigsegv; 280 281 signal = current_thread_info()->exec_domain 282 && current_thread_info()->exec_domain->signal_invmap 283 && sig < 32 284 ? current_thread_info()->exec_domain->signal_invmap[sig] 285 : sig; 286 287 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); 288 289 if (_NSIG_WORDS > 1) 290 err |= __copy_to_user(frame->extramask, &set->sig[1], 291 sizeof(frame->extramask)); 292 293 /* Set up to return from userspace. If provided, use a stub 294 already in userspace. */ 295 if (ka->sa.sa_flags & SA_RESTORER) { 296 regs->pr = (unsigned long) ka->sa.sa_restorer; 297 #ifdef CONFIG_VSYSCALL 298 } else if (likely(current->mm->context.vdso)) { 299 regs->pr = VDSO_SYM(&__kernel_sigreturn); 300 #endif 301 } else { 302 /* Generate return code (system call to sigreturn) */ 303 err |= __put_user(MOVW(7), &frame->retcode[0]); 304 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 305 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 306 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 307 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 308 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 309 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 310 err |= __put_user((__NR_sigreturn), &frame->retcode[7]); 311 regs->pr = (unsigned long) frame->retcode; 312 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 313 } 314 315 if (err) 316 goto give_sigsegv; 317 318 /* Set up registers for signal handler */ 319 regs->regs[15] = (unsigned long) frame; 320 regs->regs[4] = signal; /* Arg for signal handler */ 321 regs->regs[5] = 0; 322 regs->regs[6] = (unsigned long) &frame->sc; 323 324 if (current->personality & FDPIC_FUNCPTRS) { 325 struct fdpic_func_descriptor __user *funcptr = 326 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 327 328 err |= __get_user(regs->pc, &funcptr->text); 329 err |= __get_user(regs->regs[12], &funcptr->GOT); 330 } else 331 regs->pc = (unsigned long)ka->sa.sa_handler; 332 333 if (err) 334 goto give_sigsegv; 335 336 set_fs(USER_DS); 337 338 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 339 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 340 341 return 0; 342 343 give_sigsegv: 344 force_sigsegv(sig, current); 345 return -EFAULT; 346 } 347 348 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 349 sigset_t *set, struct pt_regs *regs) 350 { 351 struct rt_sigframe __user *frame; 352 int err = 0; 353 int signal; 354 355 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 356 357 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 358 goto give_sigsegv; 359 360 signal = current_thread_info()->exec_domain 361 && current_thread_info()->exec_domain->signal_invmap 362 && sig < 32 363 ? current_thread_info()->exec_domain->signal_invmap[sig] 364 : sig; 365 366 err |= copy_siginfo_to_user(&frame->info, info); 367 368 /* Create the ucontext. */ 369 err |= __put_user(0, &frame->uc.uc_flags); 370 err |= __put_user(NULL, &frame->uc.uc_link); 371 err |= __save_altstack(&frame->uc.uc_stack, regs->regs[15]); 372 err |= setup_sigcontext(&frame->uc.uc_mcontext, 373 regs, set->sig[0]); 374 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 375 376 /* Set up to return from userspace. If provided, use a stub 377 already in userspace. */ 378 if (ka->sa.sa_flags & SA_RESTORER) { 379 regs->pr = (unsigned long) ka->sa.sa_restorer; 380 #ifdef CONFIG_VSYSCALL 381 } else if (likely(current->mm->context.vdso)) { 382 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); 383 #endif 384 } else { 385 /* Generate return code (system call to rt_sigreturn) */ 386 err |= __put_user(MOVW(7), &frame->retcode[0]); 387 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 388 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 389 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 390 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 391 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 392 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 393 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); 394 regs->pr = (unsigned long) frame->retcode; 395 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 396 } 397 398 if (err) 399 goto give_sigsegv; 400 401 /* Set up registers for signal handler */ 402 regs->regs[15] = (unsigned long) frame; 403 regs->regs[4] = signal; /* Arg for signal handler */ 404 regs->regs[5] = (unsigned long) &frame->info; 405 regs->regs[6] = (unsigned long) &frame->uc; 406 407 if (current->personality & FDPIC_FUNCPTRS) { 408 struct fdpic_func_descriptor __user *funcptr = 409 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 410 411 err |= __get_user(regs->pc, &funcptr->text); 412 err |= __get_user(regs->regs[12], &funcptr->GOT); 413 } else 414 regs->pc = (unsigned long)ka->sa.sa_handler; 415 416 if (err) 417 goto give_sigsegv; 418 419 set_fs(USER_DS); 420 421 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 422 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 423 424 return 0; 425 426 give_sigsegv: 427 force_sigsegv(sig, current); 428 return -EFAULT; 429 } 430 431 static inline void 432 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs, 433 struct sigaction *sa) 434 { 435 /* If we're not from a syscall, bail out */ 436 if (regs->tra < 0) 437 return; 438 439 /* check for system call restart.. */ 440 switch (regs->regs[0]) { 441 case -ERESTART_RESTARTBLOCK: 442 case -ERESTARTNOHAND: 443 no_system_call_restart: 444 regs->regs[0] = -EINTR; 445 break; 446 447 case -ERESTARTSYS: 448 if (!(sa->sa_flags & SA_RESTART)) 449 goto no_system_call_restart; 450 /* fallthrough */ 451 case -ERESTARTNOINTR: 452 regs->regs[0] = save_r0; 453 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 454 break; 455 } 456 } 457 458 /* 459 * OK, we're invoking a handler 460 */ 461 static void 462 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, 463 struct pt_regs *regs, unsigned int save_r0) 464 { 465 sigset_t *oldset = sigmask_to_save(); 466 int ret; 467 468 /* Set up the stack frame */ 469 if (ka->sa.sa_flags & SA_SIGINFO) 470 ret = setup_rt_frame(sig, ka, info, oldset, regs); 471 else 472 ret = setup_frame(sig, ka, oldset, regs); 473 474 if (ret) 475 return; 476 signal_delivered(sig, info, ka, regs, 477 test_thread_flag(TIF_SINGLESTEP)); 478 } 479 480 /* 481 * Note that 'init' is a special process: it doesn't get signals it doesn't 482 * want to handle. Thus you cannot kill init even with a SIGKILL even by 483 * mistake. 484 * 485 * Note that we go through the signals twice: once to check the signals that 486 * the kernel can handle, and then we build all the user-level signal handling 487 * stack-frames in one go after that. 488 */ 489 static void do_signal(struct pt_regs *regs, unsigned int save_r0) 490 { 491 siginfo_t info; 492 int signr; 493 struct k_sigaction ka; 494 495 /* 496 * We want the common case to go fast, which 497 * is why we may in certain cases get here from 498 * kernel mode. Just return without doing anything 499 * if so. 500 */ 501 if (!user_mode(regs)) 502 return; 503 504 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 505 if (signr > 0) { 506 handle_syscall_restart(save_r0, regs, &ka.sa); 507 508 /* Whee! Actually deliver the signal. */ 509 handle_signal(signr, &ka, &info, regs, save_r0); 510 return; 511 } 512 513 /* Did we come from a system call? */ 514 if (regs->tra >= 0) { 515 /* Restart the system call - no handlers present */ 516 if (regs->regs[0] == -ERESTARTNOHAND || 517 regs->regs[0] == -ERESTARTSYS || 518 regs->regs[0] == -ERESTARTNOINTR) { 519 regs->regs[0] = save_r0; 520 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 521 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { 522 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 523 regs->regs[3] = __NR_restart_syscall; 524 } 525 } 526 527 /* 528 * If there's no signal to deliver, we just put the saved sigmask 529 * back. 530 */ 531 restore_saved_sigmask(); 532 } 533 534 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, 535 unsigned long thread_info_flags) 536 { 537 /* deal with pending signal delivery */ 538 if (thread_info_flags & _TIF_SIGPENDING) 539 do_signal(regs, save_r0); 540 541 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 542 clear_thread_flag(TIF_NOTIFY_RESUME); 543 tracehook_notify_resume(regs); 544 } 545 } 546